They don't like being called migrants, but for these self-styled "workampers," their RV isn't just their only home -- it's some 400 square feet of mobile opportunity.

Jobs typically last between three and five months in sites ranging from state parks to Florida's Walt Disney World. Today, a good number of those available jobs are in Campbellsville, Ky., where a large processing plant for Amazon.com is still hiring workers for the busy holiday season.

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More than 500 families have settled in a campground set up by Amazon, taking jobs in the company's plant for nearly $15 an hour. All told, Amazon has hired 15,000 temporary workers at similar processing plants nationwide.

"There are jobs everywhere for people that live in RV's and are willing to move around," said Shelia Sowder, a retiree who's taken a job at Amazon's Kentucky plant.

Sowder and her husband Jimmy, a former truck driver, are from Indianapolis, but they've been traveling the country for three years. While they're parked in Kentucky, Amazon pays their rent and all utilities.

"It's a fantastic deal," Jimmy Sowder said.

Websites Link Mobile Workers with Employers

Websites help link employers with RV owners looking for jobs. At Workamper.com, paid subscribers have access to a database of job listings. According to the editor of the site, Steve Anderson, the community of "workampers" in the United States numbers around half a million people.

Often, these workers are retirees looking to earn money as they crisscross the United States, but some down-on-their-luck families have also turned to the highway for a leg up.

Heather Wickline and her family are from Tampa, where her husband lost his job in December. The couple are now on the road with their school-age children, and today, he's at work. The kids are happy, and there's a job waiting when the Amazon work ends.

"We just got a job offer from Louisville, but we're hoping to go someplace south, like Texas or Florida," Wickline said.

"Workamping" Life Can Be Tough

Still, in no way is it an easy lifestyle. Families say they have to live with a lot of uncertainty, and they have to be willing to leave new friendships behind.

In the last year, the Sowders have worked in New Mexico and Kentucky, and they'll spend the holidays in Indianapolis and Boston. Come April, they'll start seasonal work in Maine.